電子信息技術(shù)專業(yè)英語-教學 Unit-4

Unit

4

Operational

Amplifier1運算放大器一.NEWWORDS21.amplifier

[??mpli?fai?

]

n.放大器，擴音器2.analogue

[??n?l?ɡ]n.模擬

adj.模擬的3.variety

[v??rai?ti

]

n.變化,多樣性,種類4.discrete

[

dis?kri:t]adj.不連續(xù)的,

離散的5.internal

[in?t?:nl

]

adj.內(nèi)在的,

國內(nèi)的6.denote

[di?n?ut

]vt.指示,

表示7.invert

[in?v?:t

]vt.使顛倒,

使轉(zhuǎn)化8.available

[??veil?bl

]adj.可獲得的9.package

[?p?ki?

]n.包裹,包,管殼? 10.pin

[pin

]n.釘,管腳，引線11.impedance

[im?pi:d?ns

]n.[電]阻抗，阻抗1.operational

amplifier 運算放大器???3invertinginputnon-invertinginput8pindual-in-line反向輸入端同向輸入端8管腳雙列直插式二.Technicalterms:三.

Expressions:4avariety

ofeventhoughbeinterested

inbeknownaswithrespecttobeequalto各種各樣的即使對...感興趣被稱為…關(guān)于,至于等于，與…相等四.

Questions

for

text

discussion:51.Whyisoperational

amplifier

giventhename?2.Drawthecircuit

symbolofanoperational

amplifier.3.Talkabouttheapplication

oftheoperational

amplifier.The

first

paragraph: Theoperational

amplifier

isthemostimportantbasic

blockofalllinear

circuits.

Ithas

awiderangeapplications

insuch

fieldsasanalogue

signaloperations,amplification,

filtering,

waveformsproducing,linear

andnon-linearsignalshanding,etc.譯：運算放大器是所有線性電路中最重要的基本器件。它的應(yīng)用十分廣泛，包括模擬信號的運算，放大，濾波，波形發(fā)生器，以及進行線性和非線性信號的處理等。6五

Learnthetext:Thesecondparagraph:Theterm

“operational

amplifier”

wasoriginally

applied

tohighgainamplifiers

operatingdowntozerofrequencywhichwereusedinanalogue

computerstoperformcertain

mathematicaloperations.Thesehighgainamplifier

arenowusedfor

awidevariety

ofapplications,

butthename

“operational

amplifiers”

or“op-amp”

isnormallyuseeventhoughnomathematical

operationareinvolved.

Theearlyoperational

amplifieremployed

discretecomponents,

butitisnowmuchmoreconvenient

toemployanintegrated

circuit.

Thecircuit

designersisnotgenerally

interestedintheinternal

components

ofanintegrated

circuit,

butonly

intheperformance

oftheunitas

awhole.Therefore,thesymbolinFig.2isusedtodenote

theamplifier.

Itcan

beseen

that

there

aretwoinputs,oneoutputandconnection

thepositive

andnegativesupplylines.7注：這里

whichwere used…mathematical

operational

為定語從句，修飾前面的 highgainamplifiers,

因為定語從句并未直接跟在所修飾的先行次后，語法上稱其為分割定語。而定語從句中的

toperformcertain

mathematical

operations

為動詞不定式短語，作目的狀語。8?

譯：運算放大器這一術(shù)語最早適用于下限頻率可低到零赫茲的高增益放大器，它可用于模擬計算機中執(zhí)行某些數(shù)學運算。這種高增益的放大器現(xiàn)在已被廣泛應(yīng)用于各個方面，早已遠遠超出數(shù)值運算的范圍，但通常仍稱之為運算放大器或OP-

AMP。早期的運算放大器適用分立元件，但現(xiàn)在適用集成電路就更為方便了。電路設(shè)計者通常對集成電路內(nèi)波元件并不感興趣，只關(guān)心作為一個整體的單元性能。因此，圖2所示的符號用來表示運算放大器。由圖可見，運放有兩個輸入端，一個輸出端以及正、負電源端子。9Thethird

paragraph:10Iftheinvertinginputismadeslightlymorepositive,

theoutputwillbecome

morenegative,

thisiswhythename“inverting”

isgiventothisinput.if,thenon-invertinginputismade

morepositive,theoutputwillalsobecomemorepositive.譯：如果反向輸入端正電壓略微增加一點，那么輸出負電壓變得更強，這就是為什么稱這個輸入端為“反向輸入端” 的原因。然而，如果同相收入電壓正向增大，輸出端正電壓也將變得更強。11Thefourth

paragraph:Type741device

isoneofthebestknowngeneralpurposeoperational

amplifier

andisalsooneofthecheapest

ofall

linear

integrated

circuits.

Thedevice

isactually

available

in

anumberofdifferentpackages.Readerswillusuallyfindthetypeof741showninFig.3.Thistypeofpackage

isknownasthe8pindual-in-line.譯：741型器件是眾所周知的通用運算放大器之一，也是所有的線性集成電路中最便宜的一種。這種器件實際上具有不同的封裝形式。讀者通常會發(fā)現(xiàn)如圖3所示的741型器件最便于使用，這種封裝形式為8管腳雙列直插式11Thefifthparagraph:12Abasic

circuit

ofa741inverting

amplifierisshowninFig.4.Theinputsignalisfedtothe

invertinginputof741viaR1andthereforetheoutputisinverted

inphaserespect

totheinput.Operational

amplifier

aredesignedtohave

averyhighinputimpedance.

Theinputcurrentsofthe741circuit

arethereforeverysmall.Astheinvertinginputisvirtually

atgroundpotential,thecurrentwhichflowsthroughR1

isequal

totheinputvoltageUi

dividedbyR1.Similarly,

thecurrentflowingthrough

R3

is–Uo/R3.where

Uo

istheoutputvoltage.

Thesetwocurrentarealmostequal,

thusthevoltage

gainofcircuit

isequal

totheresistorvalues

G=

-R3/R1.?

譯 : 741反向放大器的基本電路如圖4所示。輸入信號經(jīng)R1加在741器件的反相輸入端，因此輸出信號與輸入信號的相位相反。運算放大器設(shè)計成具有很高的輸入阻抗，因此741的凈輸入電流非常小。由于反相輸入端虛短，流過R1的電流等于Ui除以R3，同樣流過R3的電流等于-Uo/R3，其中Uo輸出電壓。這兩個電流幾乎相等，因此電路的電壓增益取決于電阻值：G

=

-R3/R11314Dotheexercises:1.Translate

thefollowing

phrasesandexpressions.? (1)運算放大器?(2)to

benot

generally

interested

intheinternal

components

ofanintegratedcircuit? (3)正、負電源端? (4)8管腳雙列直插式集成塊(5)to

bevirtually

atground

potential5.Translate

thefollowing

sentencesinto

English.? (1)運算放大器是一種高增益的放大器。? (2)741器件是最常用也是最便宜的集成電路之一。? (3)將輸入信號加到運放的同相輸入端。Answer:Op-ampis

akind

ofhigh

gain

amplifier.Type741is

oneofthemost

commonly

used,andthecheapestIC.Applythe

input

signal

tothe

non-inverting

inputof

op-amp.14Reading:OscillatorTranslatethisparagraphintoChinese: Aunitthatgenerates（產(chǎn)生）

asignaliscalledanoscillator（振蕩器）.OscillatorsareusedtoprovideACsignalsfromfrequencies（頻率）

justabovezero

tofrequencies

inthegigahertz（千兆赫）

regionatthetopendoftheradio-frequencypartoftheelectromagnetic

spectrum（電磁波譜）.

Theymaybedescribedinoneoftwowaysintermsofthetypeofsignalwaveformgenerated:sinusoidal

oscillators

and

relaxationoscillators（張弛振蕩器）.

Asinusoidal

oscillator

generatesasignalhavingasinewaveform;arelaxationoscillatorgeneratesasignalthatisusuallyofsquarewaveform.15Dialogue:Amplifier

Design16Supervisor:

Iwouldlikeyoutodo

apreliminary

calculation

foranamplifier.Engineer:

Whatarethedetails?

Howistheamplifier

tobeused???Supervisor:Itmustgiveavoltagegainofabout1000.Engineer:

Thatisn’tenoughinformation.

Ineedtoknowthedesiredinputimpedanceaswellasthetypesofloadstobeusedwiththeamplifier.Supervisor:Itmusthave

ahighinputimpedance

withaninputcapacitance

ofno